We plan to continue our studies on the mechanisms of action of antitumor antibiotics. In particular, we are studying the nature and mechanism of the damage induced in DNA by the protein antibiotic, neocarzinostatin. Such damage can be induced in HeLa cells in culture or in vitro with isolated DNA. We are exploring the possible relationship between the two observations. We are also studying the action of other protein antibiotics such as auromomycin and macromomycin.